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Mod For a Sansamp RPM

Discussion in 'Amps and Cabs [BG]' started by Growly Lytes, May 13, 2010.

  1. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    I found this post` but can this done with an RPM or RBI ? If it can you could maybe mix a clean sound with a dirty sound if you have a Stereo amp.

    According to Lloyd Schwartz at Tech21, the SansAmp can be modded so that its XLR output can put out up to +4 dBu, which is enough to drive a PLX 2402 to full power.

    Here's what he wrote :

    When you remove the back cover of the Bass Driver, you'll see a "black box".
    Just to
    the right of its lower right corner, there's a resistor surrounded by two
    It looks like this:

    >O< (except it's square)

    Remove it, and you're done!

    BTW, the resistor is an SMT type (a small black rectangular shape].
    Well, a larger signal is a boost in volume. I don't know for sure if it'll affect tone, but probably not.
    Has anybody modded an RPM or RBI so the XLR puts +4db ??
  2. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    The mod you're talking about was only for the original BDDI pedals, not the RBI or RPM. To the best of my knowledge nobody has suggested or requested mods to boost the output of the RBI or RPM. Do you have one currently, and is it not driving your power amp adequately?
  3. Christian Waiau

    Christian Waiau

    Jun 16, 2005
    las vegas/maui, nevada/hawaii
    Endorsing Artist: Spector, Aguilar, Darkglass
    cant this already drive a poweramp? maybe im missing something..
  4. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    i have no idea why you'd want to get more output out of an RPM. IME, it already has more than enough output to drive even the least sensitve poweramps. the manaul says: Maximum Output Level: +10dB or better.
  5. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    NO i meant to make the uneffected (XLR) output stronger so that you wouldnt need to two preamps.
    The idea is to mix the uneffected & effected signals without using another Preamp. The uneffected signal is not strong at all but if it could be modded so you wouldnt need to purchase another preamp to get the dry signal to your stereo amp.
    When i do this at home the level of the effected signal is on about 1 or 2 where the uneffected is nearly full blast.
    So if you could boost the dry signal you could mix dry & wet properly using only 1 preamp.
  6. king rew

    king rew

    Feb 18, 2009
    Is that what the blend knob is for? I don't know, I don't have a sansamp but I've been wanting one to mix dirty/clean tones...
  7. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    Yes, Blend controls the mix of dry and wet signal, but only for the effected output. I'm guessing that Growly wants to run a stereo power amp into two speaker cabs, with one cab getting the wet signal and the other one being dry.
  8. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Ah, OK, I get it now. Growly, the mod you read about does not apply to the DI output of the RPM or RBI. It would certainly be possible to add a gain stage in there though, so you should talk to a pedal-builder in your area. Just tell them you need a FET or opamp clean boost with about 40 dB gain. Just for perspective, it's way way more involved than just removing a resistor, but for a pedal-effect-type circuit building person it's a fairly simple project.
  9. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    Thank you so its possible to do thats great, i should have said the DI but it slipped the mind.When i have a jam at home & try mixing the Dry & Wet signals & i get some really nice tones.
    The Blend Knob does mix wet & dry but its not really dry......the EQ is effecting the signal. So you really cant get a truley Dry signal using the Blend. I read somewhere a guy was trying to set-up a fake stereo rig at home with a clean dry signal to 1 cab & a super wet signal in the cab & was getting nice sounds so i tried it.
    Now if i do this to the DI will i still be able to use the output like normal, wont it be way to hot of a signal ???
    The RPM is supposed to be a rackmount version of the Sansamp Acoustic DI pedal with the added Drive control !!!
    Lets see how we shall we.
    Keep Rockin,Pluckin & Pickin
  10. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    If the pedal guy installs the extra gain stage right before the XLR jack, it will not affect the other outputs. If you want to still be able to use that XLR jack for a DI sometimes, then have the guy install a bypass toggle switch, to bypass the added gain stage.

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